System for optically aiming a laser beam on to a target

Abstract

System for optically aiming a laser beam on to a target. The system comprises a mirror which reflects the laser beam towards the target and which is supported by a base by means of a pivot and first and second vibrating control members. This pivot and the control members together determine a first mirror rotation axis and a second mirror rotation axis perpendicular to the first axis. Means are provided for respectively generating a first and a second reference signals for driving the mirror. A laser radiation detector receives the laser radiation reflected by the target and produces a reception signal from which are derived first and second reaiming signal components. The first and second vibrating control members are operated by respectively the sum of the first reference signal and the first reaiming signal component and the sum of the second reference signal and the second reaiming signal component.

What we claim is: 
     
       1. A system for optically aiming a laser beam on to a target comprising: a mirror which reflects the laser beam towards the target;   a pivot for said mirror;   first and second vibrating control members for determining with the pivot a first mirror rotation axis and a second mirror rotation axis perpendicular to the first axis and controlling the angular position of the mirror around said axes;   first and second means for respectively generating a first reference signal having a given frequency and a second reference signal having the same frequency as the first reference signal and in phase-quadrature therewith;   a laser radiation detector receiving the laser radiation reflected by the target and producing a reception signal;   sensor means for detecting the angular positions of the mirror around said first and second rotation axes and generating first and second mirror position signals;   means for differentiating the reception signal and detecting the zeros of the reception differentiated signal;   means for producing timing pulses coinciding with the zeros of said reception differentiated signal;   means for sampling the first and second mirror position signals and the reception signal by said timing pulses whereby forming signals proportional to the maximum and to the minimum of the reception signal;   computer means for forming the difference of said maximum proportional reception signal and minimum proportional reception signal and the ratio of said difference to the maximum proportional reception signal, whereby obtaining a resulting signal;   means for multiplying said resulting signal by respectively said first and second sampled mirror position signals, whereby obtaining first and second multiplied signals;   means for synchronously detecting said first and second multiplied signals by respectively said first and second reference signals whereby obtaining first and second reaiming signal components; and   means for operating said first and second vibrating control members by respectively the sum of the first reference signal and the first reaiming signal component and the sum of the second reference signal and the second reaiming signal component.   
     
     
       2. A system for optically aiming a laser beam on to a target comprising: a mirror which reflects the laser beam towards the target;   a pivot for said mirror;   first and second vibrating control members for determining with the pivot a first mirror rotation axis and a second mirror rotation axis perpendicular to the first axis and controlling the angular position of the mirror around said axes;   means for generating a first reference signal having a first predetermined frequency;   means for generating a second reference signal having a second predetermined frequency, different from said first frequency;   a laser radiation detector receiving the laser radiation reflected by the target and producing a reception signal;   two pass band filters respectively tuned to said first and second frequency and both filtering said reception signal for respectively delivering a first and a second re-aiming signal components; and   means for operating said first and second vibrating control members by respectively the sum of the first reference signal and the first re-aiming signal component and the sum of the second reference signal and the second re-aiming signal component.   
     
     
       3. An aiming system as claimed in claim 2 wherein the first and second vibrating control members are constituted respectively by a first and second support of piezo-electric material. 
     
     
       4. A system for optically aiming a laser beam on to a target comprising: a mirror which reflects the laser beam toward the target;   a pivot for said mirror;   first and second vibrating control members for determining with the pivot a first mirror rotation axis and a second mirror rotation axis perpendicular to the first axis and controlling the angular position of the mirror around said axes;   means for generating a first reference signal having a given frequency and a second reference signal having the same given frequency and in phase-quadrature with the first reference signal;   a laser radiation detector receiving the laser radiation reflected by the target and producing a reception signal;   two synchronous detectors both receiving the reception signal and respectively receiving said first and second reference signals for respectively delivering a first and second re-aiming signal component; and   means for operating said first and second vibrating control members by respectively the sum of the first reference signal and the first re-aiming signal component and the sum of the second reference signal and the second re-aiming signal component.   
     
     
       5. An aiming system as claimed in claim 4 wherein the first and second vibrating control members are constituted respectively by a first and second support of piezo-electric material. 
     
     
       6. A system for optically aiming a laser beam on to a target comprising: a mirror which reflects the laser beam towards the target;   a pivot for said mirror;   first and second means for respectively generating a first and a second reference signal;   a laser radiation detector receiving the laser radiation reflected by the target and producing a reception signal;   means for deriving from said reception signal first and second re-aiming signal components;   
     
     
       a first vibrating control member for determining with the pivot a first mirror rotation axis, said control member comprising a first support of piezo-electric material operated by the first reference signal and a second support of piezo-electric material operated by the first re-aiming signal component; and a second vibrating control member for determining with the pivot a second mirror rotation axis, said control member comprising a third support of piezo-electric material operated by the second reference signal and a fourth support of piezo-electric material operated by the second re-aiming signal component.